Zika virus (fever Zeke ) - Causes, Symptoms and Treatment .MF .

August 12, 2017 17:52 | Infectious Diseases

virus Zika or fever Zika - zooantraponoznoe (transmitted from a human to a human animal) natural-focal (dwelling under certain climatic conditions) arbovirus (transmitted chlenestonogimi insects) infection with transmissible pathogen transmission mechanism (through the bites of infected mosquitoes in thiscase - genus Aedes), characterized by sudden onset, fever, intoxication syndrome, sometimes haemorrhagic and meningeal symptoms can ikterichnost skin and sclera.

transporter Zika virus - a mosquito genus Aedes

reasons Zika virus

Pathogen: RNA-containing arbovirus of the family Flaviviridae genus Flavivirus.Zika virus refers to a complex of Uganda, Banse and Spondveni.The nucleocapsid contains a protein with antigenic properties and group-typical specificity - which determines the symptoms and course.

Pathogen Zika virus is not very stable in the environment and is easily inactivated by heat and ordinary disinfectants.

But the influence of destructive factors, a virus characterized by a high

rate of reproduction and the development of cytopathic effects (degenerative changes in cells) in many cell cultures, including cells bearing Fc receptors of macrophages and lines of these cells (natural killer cells, neutrophils and mast cells), in which the virus yield is increased in the presence of specific antibodies. Ie instead of the expected elimination of the pathogen in the immune response, there is still a large activation of the virus!

high rate of reproduction observed in cultures of cells of mosquitoes, but no cytoplasmic effect (ie, a virus reproduces itself, without the devastating effects on the host cell) - it is attached to the cells due to the receptor glycoprotein E1 and E2, enters the cellby endocytosis and replicates in the cytoplasm, and only partially including nucleic acid and protein synthesis of host cells of mammals, but does not stop the operation of the arthropod cells.

infection, thus accompanied by proliferation perinuclear membranes, ie probadeniem / destruction of large areas and, as a consequence - a violation of a number of important functions at the cellular level.Said E protein induces neytraliztsyuschie antiela and other structures of protective immunity.

structure Zika virus

Referring to the structure, it is worth remembering about the tropism of the pathogen to cells of bone marrow origin, ie the virus prefers to hit the immune cells.

counterbalance the danger of the disease:

• rapid attenuation of the causative agent - ie, reduced virulence (infectivity) with frequent passages, due to the high mutation and stabilization of the mutated virus in a specific and homogeneous cell type.In this case, the example is the reduction of neurotropic and viscerotropic - ie clinical and morphological manifestations will proceed more smoothly from subsequent infected.

But on the other hand it can lead to avoiding immune control, because the immune system cells can not fully recognize the pathogen.

Epidemiology Zika virus

reservoir and source of pathogens - mainly the Aedes mosquito genus, living in countries with a humid climate (the territory of left-bank Ukraine), in temperate countries (Black Sea coast).But for now, for several decades since its discovery, Zika virus was recorded in the south-western, central and eastern Africa, and Southeast Asia, but the virus had sporadic disease without mass manifestations.

Since 1947, when the virus was discovered, and to this epidemic occurred in 2015, when the virus preobrel massive, ill one and only in the equatorial and tropical zones, the disease proceeded relatively well and did not cause any great concern.

At the beginning of 2016, the virus has already covered 23 countries and has found a link between the disease and malformations of the nervous system of the fetus with infected mothers during pregnancy.So far, the risk of disease in Russia is minimized, due to climatic conditions, but it is impossible to exclude the end.

scheme of the disease from the moment the virus enters the body:

• After penetration through the skin by the bite of a mosquito, the virus enters the bloodstream, but initially infect dendritic cells, the introduction of near space.

• reproduction step further occurs which is carried out in lymph node endothelium and reticuloendothelial cells in Zika virus antigens localized in the nuclei of affected cells and not in the cytoplasm.Based on the tropism blood breeding (for diagnosis) appears first picture leukopenia, and after - leukocytosis.

• As a result of tropism for cells of RES (reticuloendothelial system), having a total prevalence, there is a risk of local viral replication: in the liver, brain, kidneys.On this basis, will unfold and symptoms: fever, headache, myalgia, arthralgia, finely-papullёznaya rash, conjunctivitis, ikterichnost skin and visible mucous membranes.

• To date, a significant number of cases, the clinical manifestations were limited to periods of dissemination of viruses, followed by recovery without consequences. At the moment, for acquired other contours - with a bright clinical picture, and more severe complications: fever may be complicated by hemorrhagic symptoms as a result of vascular disorders, is manifested in the form of bleeding mucous without traumatizing factor;Fever can take a two-wave current, which at the height of the second wave, new clinical and laboratory changes (albuminuria, meningeal signs, encephalitis, myelitis), speaking in favor of the secondary organ damage.

symptoms of Zika virus

1.Vnezapnoe beginning with the dominance of one or more symptoms early in the disease: weakness, headache, fever up to seven days with temperatures up to 39-40 C, fine-spotted rash, myalgia and arthralgia (pain in the musclesand joint), conjunctivitis (eye inflammation), ikterichnost (yellowness) of the skin and mucous membranes.

2.Techenie fever can be two-wave, that is, the temperature will rise after declining again.

3. Possible secondary organ injury mediated predominantly viral lesions.Depending on the affected organ (s) appear certain symptoms of brain and / or focal neurological symptoms, symptoms of liver and kidney failure, vascular lesions in the form of finely-point rash and bleeding.

Zika virus Diagnosis

priority in serological diagnosis of DGC, HI, RNIF, ELISA methods;PCR tests in the acute phase of the disease, or no later than 5 days after.

treatment of disease caused by a virus Zika

Unfortunately, the specific treatment of the virus is not present, and in the arsenal is only symptomatic and pathogenic, ie effects on the symptoms and the main link of pathogenesis.

There is an option of using immunomodulatory and immunostimulatory therapy in determining the impairment of the immune level, specific drugs determined by the physician of the conventional drugs such as TSikloferon, Viferon, polioksidony, Likopid others, but clinical guidelines at the time of the Russian Federation is not, they are in the processdevelopment.

If signs of central nervous system drugs such groups are used as diuretics (for hypertension vnutricherepnomozgovoy) degidrotatsionnuyu therapy, if necessary - spinal tap.

In order to prevent secondary bacterial complications appointed broad-spectrum antibiotics, tetracycline and chloramphenicol except for adverse effects on blood vessels.

Uzkospektornaya antiviral therapy is currently under development and is dependent on the full collection and analysis of information about the virus.

forecast

The disease with an incubation period extends to 14 days, of which 3 to 7 days the midst of all the symptoms (if they occur, to 30% of diseases can be asymptomatic or confused with other diseases), duration of the diseasedoes not depend on the treatment, it only facilitates the clinical picture.

most often (except pregnant women) does not cause any complications and passes almost unnoticed with complete recovery.

As for pregnant women, the evidence base for their treatment there, and therapeutic measures often do not prevent complications associated with microcephaly in the fetus.In many countries, there are recommendations to refrain from procreation nearest to eliminate the spread and to find optimal treatments that are planning to develop by the end of 2016 and beginning of 2017 to carry out their clinical trials.

microcephaly - a malformation of the fetal brain, the disease is a result of violation of the migration and differentiation of nerve cells.Microcephaly is characterized by a decrease in brain volume, so that the child develops mental retardation.

In the Russian Federation the disease and spread of the virus is highly unlikely due to the nature of our climate in which it is impossible to realize the carrier lifetime.But there are episodic diseases due to globalization and the lack of large periods of movement between the two countries, resulting in a possible isolated cases due to infection in the third countries or skid insect virus carrier.

also has one confirmed case of transmission through sexual contact, which can be a serious challenge to humanity and have a poor prognosis with the spread of infection.

Prevention Zika virus

Currently, the most important protective measures are the fight against the mosquito populations and preventing mosquito bites among people at risk, especially among pregnant women.

Vaccine is not designed, conducted research on its creation, many countries have announced its creation in 2017, including the Russian Federation.

therapists Shabanova IE